Thrips and Cotton Update

A lot of cotton has been planted this week (May 13-17). This is the first time many areas have been dry enough since early April. However, believe it or not, much of central Alabama missed rains in the last weather front and it is already too dry for seed to germinate.

Cotton that has emerged has not made much growth to this point. Cloudy weather, cool nights and a moderate number of thrips has severely hampered seedling growth. Based on my observations from monitoring four thrips research trials, I would suggest that the cooler than normal temperatures, especially at night, has done more to prevent seedling plant growth than has thrips injury.

Thrips numbers have not been abnormally high. In fact, it does not appear that the mass movement of thrips from grains and other wild host plants have occurred yet. Thrips damage is moderate to heavy primarily due to the fact that plants are not growing due to cool nights.

Cotton planted this week (May 13-17) should have better growing conditions and grow off rapidly. If that is the case, thrips injury will be minimal in spite of thrips numbers.

I would suggest that cotton emerging after May 20 will not need a foliar spray to supplement seed treatments. My thrips trials planted on April 10 did not emerge and put on a true leaf until more than 21 days after planting. In this situation, much of the thrips control provided by the seed treatments had dropped considerably before a true leaf even emerged.

The bottom line is that growing conditions, moisture and temperature are more important than thrips numbers or the type of thrips control a grower chooses.



No seed treatment and no foliar spray. Plant date 4/10/13.



Seed treatment and foliar spray. Plant date 4/10/13.